Rotary compressor and air conditioner having the same

ABSTRACT

A rotary compressor is provided, including: a rotation shaft; a driving motor which is coupled to a first side of the rotation shaft to supply a rotation force; a rotation cam which is eccentrically provided to a second side of the rotation shaft and supports a rolling piston rotating inside a cylinder which is provided under the driving motor; an upper radial bearing and a lower radial bearing which are provided to an upper part and a lower part of the rolling piston and support the rotation shaft in a radial direction; and an axial supporting part which comprises a first supporting member which is provided between the driving motor and the upper radial bearing, and a second supporting member which is provided between the rotation cam and the lower radial bearing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Korean Patent Application No. 10-2007-0001439, filed on Jan. 5, 2007, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

The present invention relates to a rotary compressor and an air conditioner having the same related to improving a configuration supporting a rotation shaft.

2. Description of the Related Art

Generally, an air conditioner operates in a heating mode and a cooling mode according to a demand of a user. The air conditioner heats a room in the heating mode in winter, and cools the room in the cooling mode in summer. Also, the air conditioner adjusts humidity of the room, and cleans air of the room.

Generally, the air conditioner includes an indoor unit mounted with an indoor heat exchanging unit and an indoor fan cooling or heating a room, and an outdoor unit mounted with an outdoor heat exchanging unit, an outdoor fan and a rotary compressor.

In a heating cycle of the heating mode, at first, the rotary compressor compresses a coolant. The compressed coolant is supplied to the indoor heat exchanging unit, and air heated by heat exchange is discharged into the room, thereby heating the room.

In a cooling cycle of the heating mode, at first, the rotary compressor compresses the coolant. The compressed coolant is supplied to the outdoor heat exchanging unit, and air cooled by heat exchange is discharged into the room, thereby cooling the room. The coolant passing the room is supplied to the outdoor heat exchanging unit.

In the cooling and heating processes, the rotary compressor repeats a compressing process of the coolant, and the air conditioner successively performs compression, condensation, expansion and vaporization processes.

Generally, the rotary compressor includes a driving shaft rotating by a magnetic flux variation between a stator and a rotor, a rolling piston coupled to an eccentric part of a driving shaft to rotate in an inner space of a cylinder according to rotation of the driving shaft, and a vane inserted in a side of the cylinder to rectilinearly reciprocate in a radial direction. The vane includes an end part line-contacted with an outer surface of the rolling piston to convert a space part formed by an inner surface of the cylinder and the outer surface of the rolling piston into a compressing chamber and a discharging chamber. The vane is accommodated in a vane room formed to a side of the cylinder to go into and out of the vane room toward the rolling piston.

When the rotary compressor rotates, a radial load applied in a transverse direction to a rotation shaft, and a thrust load applied in a rotation shaft direction are generated. A radial bearing supports the radial load and the thrust load.

However, in a conventional rotary compressor, since the radial bearing contact-supports the thrust load applied in the shaft direction of the rotation shaft, a load applied to a motor increases by a friction force due to contact while the motor rotates. Also, if lubrication of, for example, a contact surface is insufficient, a driving force driving the rotation shaft increases, and minute particles, etc. are likely to be mixed into a compressing chamber or other parts due to increase of friction. Also, movement of the rotary compressor is deteriorated.

SUMMARY

Accordingly, it is an aspect of the present invention to provide a rotary compressor and an air conditioner having the same reducing a load applied to a driving motor.

Another aspect of the present invention is to provide a rotary compressor and an air conditioner having the same, simplifying movement of a driving motor.

Still another aspect of the present invention is to provide a rotary compressor and an air conditioner having the same, reducing abrasion of a friction part.

Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

The foregoing and/or other aspects of the present invention can be achieved by providing a rotary compressor, comprising: a rotation shaft; a driving motor which is coupled to a first side of the rotation shaft to supply a rotation force; a cylinder under the driving motor and having a rolling piston rotating therein; a rotation cam which is eccentrically provided to a second side of the rotation shaft and supports the rolling piston; an upper radial bearing and a lower radial bearing which are provided to an upper part and a lower part of the rolling piston respectively and support the rotation shaft in a radial direction thereof; and an axial supporting part which comprises a first supporting member which is provided between the driving motor and the upper radial bearing, and a second supporting member which is provided between the rotation cam and the lower radial bearing.

According to an aspect of the invention, the axial supporting part supports an axial load of the rotation shaft when the rotation shaft rotates, and the upper radial bearing is distanced from the rotation cam when the axial supporting part is coupled to the rotation shaft.

According to an aspect of the invention, the upper radial bearing comprises a first lower surface, the rotation cam comprises an upper cam surface, and the first lower surface of the upper radial bearing is distanced from the upper cam surface.

According to an aspect of the invention, the upper radial bearing further comprises a first upper surface, the driving motor comprises a lower motor surface, and the first supporting member is coupled between the first upper surface of the upper radial bearing and the lower motor surface.

According to an aspect of the invention, the lower radial bearing further comprises a second upper surface, the rotation cam further comprises a lower cam surface, and the second supporting member is coupled between the second upper surface of the lower radial bearing and the lower cam surface of the rotation cam.

According to an aspect of the invention, the first supporting member and the second supporting member respectively comprise a thrust ball bearing, and a pair of thrust rings which are rotatably contacted to the thrust ball bearing to opposite sides of the thrust ball bearing.

The foregoing and/or other aspects of the present invention can also be achieved by providing a rotary compressor, comprising: a rotation shaft; a driving motor which is coupled to a first side of the rotation shaft to supply a rotation force; a cylinder under the driving motor having a first rolling piston and second rolling piston rotating therein; a first rotation cam and a second rotation cam which are eccentrically provided to a second side of the rotation shaft and support the first rolling piston and the second rolling piston; an upper radial bearing and a lower radial bearing which are provided to an upper part of the first rolling piston and a lower part of the second rolling piston respectively and support the rotation shaft in a radial direction thereof; and an axial supporting part which comprises a first supporting member which is provided between the driving motor and the upper radial bearing, and a second supporting member which is provided between the second rotation cam and the lower radial bearing.

According to an aspect of the invention, the axial supporting part supports an axial load of the rotation shaft when the rotation shaft rotates, and the upper radial bearing is distanced from the first rotation cam when the axial supporting part is coupled to the rotation shaft.

According to an aspect of the invention, the rotary compressor further comprises a middle plate which is interposed between the first rotation cam and the second rotation cam, wherein at least one of the first rotation cam and the second rotation cam are distanced from the middle plate.

The foregoing and/or other aspects of the present invention can also be achieved by providing an air conditioner comprising: a rotary compressor which compresses a coolant, the rotary compressor comprising: a rotation shaft; a driving motor which is coupled to a first side of the rotation shaft to supply a rotation force; a cylinder under the driving motor and having a rolling piston rotating therein; a rotation cam which is eccentrically provided to a second side of the rotation shaft and supports the rolling piston; an upper radial bearing and a lower radial bearing which are provided to an upper part and a lower part of the rolling piston respectively and support the rotation shaft in a radial direction thereof; and an axial supporting part which comprises a first supporting member which is provided between the driving motor and the upper radial bearing, and a second supporting member which is provided between the rotation cam and the lower radial bearing.

According to an aspect of the invention, the axial supporting part supports an axial load of the rotation shaft when the rotation shaft rotates, and the upper radial bearing is distanced from the rotation cam when the axial supporting part is coupled to the rotation shaft.

According to an aspect of the invention, the first supporting member and the second supporting member respectively comprise a thrust ball bearing, and a pair of thrust rings which are rotatably contacted to the thrust ball bearing on opposite sides of the thrust ball bearing.

The foregoing and/or other aspects of the present invention can be achieved by providing an air conditioner comprising: a rotary compressor which compresses a coolant, the rotary compressor comprising: a rotation shaft; a driving motor which is coupled to a first side of the rotation shaft to supply a rotation force; a cylinder under the driving motor having a first rolling piston and second rolling piston rotating therein; a first rotation cam and a second rotation cam which are eccentrically provided to a second side of the rotation shaft and support the first rolling piston and the second rolling piston; an upper radial bearing and a lower radial bearing which are provided to an upper part of the first rolling piston and a lower part of the second rolling piston respectively and support the rotation shaft in a radial direction thereof; and an axial supporting part which comprises a first supporting member which is provided between the driving motor and the upper radial bearing, and a second supporting member which is provided between the second rotation cam and the lower radial bearing.

According to an aspect of the invention, the axial supporting part supports an axial load of the rotation shaft when the rotation shaft rotates, and the upper radial bearing is distanced from the first rotation cam when the axial part is coupled to the rotation shaft.

According to an aspect of the invention, the air conditioner further comprises a middle plate which is interposed between the first rotation cam and the second rotation cam, wherein at least one of the first rotation cam and the second rotation cam are distanced from the middle plate.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects of the prevent invention will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of an air conditioner according to embodiments of the present invention;

FIG. 2 is a sectional view illustrating a first exemplary embodiment of a rotary compressor in FIG. 1;

FIG. 3 is an enlarged sectional view of part III in FIG. 2;

FIG. 4 is an enlarged sectional view of part IV in FIG. 2;

FIG. 5 is an exploded perspective view of an axial supporting part in FIG. 2;

FIG. 6 is a sectional view illustrating an operating state of FIG. 2; and

FIG. 7 is a sectional view illustrating a second exemplary embodiment of the rotary compressor in FIG. 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below so as to explain the present invention by referring to the figures.

An air conditioner according to the embodiments of the present invention may be employed to, for example, a ceiling type, a window mounting type, a floor standing type air conditioner. Hereinafter, as an exemplary embodiment according to the present invention, an air conditioner including an indoor unit and an outdoor unit will be described.

First Exemplary Embodiment

As shown in FIGS. 1 to 5, an air conditioner 100 according to a first exemplary embodiment of the present invention includes a rotary compressor 210. The air conditioner 100 includes an outdoor fan 123. The air conditioner 100 includes an indoor unit (not shown).

The air conditioner 100 further includes an outdoor heat exchanging unit 125. The air conditioner 100 further includes a casing 127 and a coolant pipe 129. The air conditioner 100 further includes a control part (not shown) electrically connected with the indoor unit to control a driving part 210 by an electrical signal and power supply with the indoor unit.

The driving part 210 includes the rotary compressor 210 and an outdoor fan 123. The driving part 210 and outdoor fan 123 may include other components driven by an inverter in addition to the rotary compressor 210 and the outdoor fan 123.

The outdoor fan 123 is disposed adjacent to the outdoor heat exchanging unit 125, and brings outdoor air to the outdoor heat exchanging unit 125 to heat-exchange the outdoor heat exchanging unit 125 and the outdoor air. The outdoor heat exchanging unit 125 is disposed adjacent to the outdoor fan 123, and widens a contact area to be heat-exchanged with the outdoor air. The casing 127 accommodates the driving part 210 and outdoor fan 123, and forms an external shape of the air conditioner 100. The coolant pipe 129 accommodates a coolant to flow between the outdoor unit 120 and the indoor unit.

Hereinafter, for purposes of description, an up and down direction in which a rotation shaft 230 of the rotary compressor 210 is assembled in a vertical state will be referred to as direction ‘Y’, a right and left direction among two transverse directions to direction ‘Y’ will be referred to as direction ‘X’, and a front and rear direction of the other transverse direction to direction ‘Y’ will be referred to as direction ‘Z’ (not shown).

The rotary compressor 210 includes the rotation shaft 230, a driving motor 220, a rotation cam 243, an upper radial bearing 250, a lower radial bearing 260 and an axial supporting part 270. The rotary compressor 210 includes a compressor casing 215, a rolling piston 241 and a cylinder 240. The rotary compressor 210 may further include an accumulator (not shown) including a gas liquid separating pipe (not shown). The rotary compressor 210 sucks and compresses the coolant evaporated in an evaporator (not shown) to raise the pressure thereof so that condensation from gas to liquid can be possible under a relatively high temperature. The rotary compressor 210 passes the coolant through the coolant pipe 129.

The compressor casing 215 forms an external appearance of the rotary compressor 210, and includes a coolant discharging hole (not shown) coupled to an upper part to guide a discharge of the compressed high pressure coolant.

The driving motor 220 includes a stator 221 receiving power to form a magnetic field, and a rotator 223 rotatably disposed to the stator 221 to be coupled to the rotation shaft 230.

The rotation shaft 230 has a long bar shape, and transmits a rotation force of the rotator 223 to the rolling piston 241. The rotation shaft 230 includes the rotation cam 243 eccentrically protruding from a shaft center in a part coupled with the rolling piston 241.

As the rotation shaft 230 rotates, a radial load applying on plane ‘X-Y’ and a thrust load applying in direction ‘Y’ are generated. The radial load of the rotation shaft 230 is supported by the upper radial bearing 250 and the lower radial bearing 260. Also, the thrust load of the rotation shaft 230 is supported by the shaft direction supporting part 270.

Accordingly, since the rotation shaft 230 does not have a friction-supported part surface-contacting in the shaft direction, the rotation shaft 230 stably rotates, thereby reducing a load of the driving motor 220.

The cylinder 240 is formed to a lower part of the compressor casing 215 to be entered by the compressed coolant. The cylinder 240 communicates with a valve (not shown), etc. so that the coolant may be inhaled and exhaled into and from the cylinder 240. The rolling piston 241 is eccentrically disposed inside the cylinder 240.

The rolling piston 241 is coupled with the rotation cam 243 of the rotation shaft 230 to rotate together with the rotation cam 243 as the rotation shaft 230 rotates.

A vane (not shown) is coupled to the cylinder 240 to move in and out of the cylinder 240 to reciprocate in direction ‘X’, a rotation direction of the rotation shaft 230. An end part of the vane is line-contacted to an outer surface of the rolling piston 241. The vane converts an inside part of the cylinder 240 into a compressing chamber and a discharging chamber.

The rotation cam 243 is provided to a lower part of the rotation shaft 230 to be coupled to the rolling piston 241. The rotation cam 243 includes an upper cam surface 245 being adjacent to the upper radial bearing 250, and a lower cam surface 247 contacted with a second supporting member 273.

The upper radial bearing 250 is coupled to the rotation shaft 230 between the rotor 223 and the cylinder 240. The upper radial bearing 250 includes a first upper surface 251 facing a lower motor surface 223 a of the rotor 223, and a first lower surface 253 facing the upper cam surface 245 of the rotation cam 243. A first supporting member 271 is adjacently coupled to the first upper surface 251. The upper radial bearing 250 supports a radial direction load of rotation of the rotation shaft 230 in an upper part.

The lower radial bearing 260 is coupled with the rotation shaft 230 in a lower part of the cylinder 240. The lower radial bearing 260 includes a second upper surface 261 facing the lower cam surface 247 of the rotation cam 243. The second supporting member 273 is adjacently coupled to the second upper surface 261. The lower radial bearing 260 supports the radial direction load of rotation of the rotation shaft 230 in a lower part.

Accordingly, the radial bearings 250 and 260 can stably support the radial direction load according to rotation of the rotation shaft 230.

The shaft direction supporting part 270 includes the first supporting member 271 and the second supporting member 273.

The upper radial bearing 250 may be distanced from the rotation cam 243 when the first and second supporting members 271 and 273 of the shaft direction supporting part 270 are coupled to the rotation shaft 230. Accordingly, since the rotation cam 243 and the upper radial bearing 250 are not surface-contacted, a friction force is not generated, thereby reducing a load of the driving motor 220. Also, when the rotation shaft 230 rotates, abrasion between the rotation cam 243 and the first lower surface 253 of the upper radial bearing 250 is prevented. Accordingly, a foreign substance due to abrasion is prevented from being mixed into the cylinder 240, thereby improving reliability of the rotary compressor 210.

The first supporting member 271 is provided between the rotor 223 included in the driving motor 220 and the upper radial bearing 250. The first supporting member 271 is coupled to the rotation shaft 230 to be adjacent to the lower motor surface 223 a of the rotor 223 and the first upper surface 251 of the upper radial bearing 250.

The second supporting member 273 is provided between the rotation cam 243 and the lower radial bearing 260. The second supporting member 273 is coupled to the rotation shaft 230 to be adjacent to the lower cam surface 247 of the rotation cam 243 and the second upper surface 261 of the lower radial bearing 260.

Accordingly, the first supporting member 271 and the second supporting member 273 can stably support the thrust load generated in direction ‘Y’, an axis direction of the rotation shaft 230.

The first supporting member 271 and the second supporting member 273 may exemplarily include a thrust ball bearing 275 and a thrust ring 277. The thrust ball bearing 275 includes a thrust ball 275 a, and a ball case 275 b supporting the thrust ball 275 a in a predetermined interval.

Alternatively, the first supporting member 271 and the second supporting member 273 may include other features as long as support is provided and the spirit of the present invention can be satisfied.

Here, the first supporting member 271 and the second supporting member 273 may be coupled to be contacted with the lower motor surface 223 a of the rotor 223 and the upper radial bearing 250, and the lower cam surface 247 of the rotation cam 243 and the lower radial bearing 260, respectively. Accordingly, while the rotation shaft 230 rotates, the rotating shaft 230 can be prevented from moving in direction ‘Y’.

As necessary, only one of the supporting members 271 and 273 may be adjacently coupled to be contacted to one of the radial bearings 250 and 260. Here, the other one of the supporting members 271 and 273 being not contacted to the radial bearings 250 and 260 may minimize an interval against the radial bearings 250 and 260, thereby preventing or minimizing movement of the rotation shaft 230 in direction ‘Y’.

With this configuration, an operating process of the rotary compressor 210 of the air conditioner 100 according to the first exemplary embodiment of the present invention will be described by referring to FIG. 6.

If power is supplied to the air conditioner 100, current is supplied to the driving motor 220 of the rotary compressor 210. Accordingly, the rotator 223 and the rotation shaft 230 coupled to the rotator 223 rotate by interaction of the stator 221 and the rotator 223. As the rotation cam 243 provided to the lower part of the rotation shaft 230 rotates, the rolling piston 241 coupled to an outer surface of the rotation cam 243 rotates. Accordingly, the sucking chamber and the compressing chamber are partitioned by means of the vane coupled to the cylinder 240 to be contacted with the rolling piston 241, and suction, compression and discharging of the coolant are repeated by rotation of the rolling piston 241.

Here, when the rotation shaft 230 rotates, a force applied in direction ‘Y’, the shaft direction of the rotation shaft 230, is supported by the shaft direction supporting part 270 including the first supporting member 271 and the second supporting member 273 and coupled to the rotation shaft 230.

That is, the thrust ball 275 a of the thrust ball bearing 275 is rolling-contacted with the thrust ring 277 to support the thrust load in direction ‘Y’ of the rotation shaft 230.

Accordingly, when the rotation shaft 230 rotates, the thrust load is supported by the shaft direction supporting part 270 to minimize a surface-contacted area against the rotation shaft 230. Accordingly, a moving load of the driving motor 220 and a load according to driving can be reduced.

Second Exemplary Embodiment

As shown in FIG. 7, an air conditioner 300 according to a second exemplary embodiment of the present invention includes a rotary compressor 310.

The rotary compressor 310 includes a rotation shaft 330, a driving motor 220 coupled to a first side of the rotation shaft 330 to supply a rotation force, and a plurality of cylinders, a first cylinder 340 a and a second cylinder 340 b eccentrically provided to a second side of the rotation shaft 330 to be provided under the driving motor 220. The rotary compressor 310 includes a first rotation cam 343 a and a second rotation cam 343 b supporting a first rolling piston 341 a and a second rolling piston 341 b respectively rotating in the first cylinder 340 a and the second cylinder 340 b. The rotary compressor 310 further includes an upper radial bearing 350 and a lower radial bearing 360 provided to an upper part of the first rolling piston 341 a and a lower part of the second rolling piston 341 b to provide support in a radial direction of the rotation shaft 330. The rotary compressor 310 includes an axial supporting part 370 including a first supporting member 371 provided between the driving motor 220 and the upper radial bearing 350, and a second supporting member 373 provided between the second rotation cam 343 b and the lower radial bearing 360.

Here, compared with the first exemplary embodiment, the rotary compressor 310 according to the second exemplary embodiment includes a multiple type rotary compressor. That is, the rotary compressor 310 according to the present exemplary embodiment includes the plurality of cylinders 340 a and 340 b including the first cylinder 340 a and the second cylinder 340 b. Here, the cylinders 340 a and 340 b may include more than two cylinders, as necessary.

Here, the shaft direction supporting part 370 supports an axial load of the rotation shaft 330 when the rotation shaft 330 rotates, and the upper radial bearing 350 may be distanced from the first rotation cam 343 a when the shaft direction supporting part 370 is coupled to the rotation shaft 330.

Also, the rotary compressor 310 further includes a middle plate 380 interposed between the first rotation cam 343 a and the second rotation cam 343 b. At least one of an interval between the first rotation cam 343 a and the middle plate 380, and an interval between the second rotation cam 343 b and the middle plate 380 may be distanced. That is, at least one of an interval between a first lower cam surface 345 b of the first rotation cam 343 a and an upper plate surface 281 of the middle plate 380, and an interval between a second upper cam surface 347 a of the second rotation cam 343 b and a lower plate surface 283 of the middle plate 380 may be distanced.

Accordingly, when the rotation shaft 330 rotates, the first rotation cam 343 a and the second rotation cam 343 b of the rotation shaft 330 are not surface-contacted to the middle plate 380, thereby obtaining the same effect as the first exemplary embodiment.

As described above, the embodiments of the present invention provide a rotary compressor and an air conditioner having the same reducing a load applied to a driving motor.

Also, the embodiments of the present invention provide a rotary compressor and an air conditioner having the same simplifying movement of a driving motor.

Also, the embodiments of the present invention provide a rotary compressor and an air conditioner having the same reducing abrasion of a friction part, and reducing a foreign substance, thereby improving reliability of a rotary compressor.

Although a few exemplary embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents. 

1. A rotary compressor, comprising: a rotation shaft; a driving motor which is coupled to a first side of the rotation shaft to supply a rotation force to the rotation shaft; a cylinder under the driving motor and having a rolling piston rotating therein; a rotation cam which is eccentrically provided to a second side of the rotation shaft and supports the rolling piston; an upper radial bearing and a lower radial bearing which are provided to an upper part and a lower part of the rolling piston respectively and support the rotation shaft in a radial direction thereof; and an axial supporting part which comprises a first supporting member which is provided between the driving motor and the upper radial bearing, and a second supporting member which is provided between the rotation cam and the lower radial bearing.
 2. The rotary compressor according to claim 1, wherein the axial supporting part supports an axial load of the rotation shaft when the rotation shaft rotates, and the upper radial bearing is distanced from the rotation cam when the axial supporting part is coupled to the rotation shaft.
 3. The rotary compressor according to claim 2, wherein the upper radial bearing comprises a first lower surface, the rotation cam comprises an upper cam surface, and the first lower surface of the upper radial bearing is distanced from the upper cam surface.
 4. The rotary compressor according to claim 1, wherein the upper radial bearing comprises a first lower surface, the rotation cam comprises an upper cam surface, and the first lower surface of the upper radial bearing is distanced from the upper cam surface.
 5. The rotary compressor according to claim 4, wherein the upper radial bearing further comprises a first upper surface, the driving motor comprises a lower motor surface, and the first supporting member is coupled between the first upper surface of the upper radial bearing and the lower motor surface.
 6. The rotary compressor according to claim 3, wherein the upper radial bearing further comprises a first upper surface, the driving motor comprises a lower motor surface, and the first supporting member is coupled between the first upper surface of the upper radial bearing and the lower motor surface.
 7. The rotary compressor according to claim 6, wherein the lower radial bearing further comprises a second upper surface, the rotation cam further comprises a lower cam surface, and the second supporting member is coupled between the second upper surface of the lower radial bearing and the lower cam surface of the rotation cam.
 8. The rotary compressor according to claim 5, wherein the lower radial bearing further comprises a second upper surface, the rotation cam further comprises a lower cam surface, and the second supporting member is coupled between the second upper surface of the lower radial bearing and the lower cam surface of the rotation cam.
 9. The rotary compressor according to claim 2, wherein the first supporting member and the second supporting member respectively comprise a thrust ball bearing, and a pair of thrust rings which are rotatably contacted to the thrust ball bearing to opposite sides of the thrust ball bearing.
 10. The rotary compressor according to claim 1, wherein the first supporting member and the second supporting member respectively comprise a thrust ball bearing, and a pair of thrust rings which are rotatably contacted to the thrust ball bearing to opposite sides of the thrust ball bearing.
 11. A rotary compressor, comprising: a rotation shaft; a driving motor which is coupled to a first side of the rotation shaft to supply a rotation force; a cylinder under the driving motor having a first rolling piston and a second rolling piston rotating therein; a first rotation cam and a second rotation cam which are eccentrically provided to a second side of the rotation shaft and support the first rolling piston and the second rolling piston; an upper radial bearing and a lower radial bearing which are provided to an upper part of the first rolling piston and a lower part of the second rolling piston respectively and support the rotation shaft in a radial direction thereof; and an axial supporting part which comprises a first supporting member which is provided between the driving motor and the upper radial bearing, and a second supporting member which is provided between the second rotation cam and the lower radial bearing.
 12. The rotary compressor according to claim 11, wherein the axial supporting part supports an axial load of the rotation shaft when the rotation shaft rotates, and the upper radial bearing is distanced from the first rotation cam when the axial supporting part is coupled to the rotation shaft.
 13. The rotary compressor according to claim 12, further comprising a middle plate which is interposed between the first rotation cam and the second rotation cam, wherein at least one of the first rotation cam and the second rotation cam are distanced from the middle plate.
 14. The rotary compressor according to claim 11, further comprising a middle plate which is interposed between the first rotation cam and the second rotation cam, wherein at least one of the first rotation cam and the second rotation cam are distanced from the middle plate.
 15. An air conditioner comprising: a rotary compressor which compresses a coolant, the rotary compressor comprising: a rotation shaft; a driving motor which is coupled to a first side of the rotation shaft to supply a rotation force; a cylinder under the driving motor and having a rolling piston rotating therein; a rotation cam which is eccentrically provided to a second side of the rotation shaft and supports the rolling piston; an upper radial bearing and a lower radial bearing which are provided to an upper part and a lower part of the rolling piston respectively to support the rotation shaft in a radial direction thereof; and an axial supporting part which comprises a first supporting member which is provided between the driving motor and the upper radial bearing, and a second supporting member which is provided between the rotation cam and the lower radial bearing.
 16. The air conditioner according to claim 15, wherein the axial supporting part supports an axial load of the rotation shaft when the rotation shaft rotates, and the upper radial bearing is distanced from the rotation cam when the axial supporting part is coupled to the rotation shaft.
 17. The air conditioner according to claim 15, wherein the first supporting member and the second supporting member respectively comprise a thrust ball bearing, and a pair of thrust rings which are rotatably contacted to the thrust ball bearing on opposite sides of the thrust ball bearing.
 18. An air conditioner comprising: a rotary compressor which compresses a coolant, the rotary compressor comprising: a rotation shaft; a driving motor which is coupled to a first side of the rotation shaft to supply a rotation force; a cylinder under the driving motor having a first rolling piston and second rolling piston rotating therein; a first rotation cam and a second rotation cam which are eccentrically provided to a second side of the rotation shaft and support the first rolling piston and the second rolling piston; an upper radial bearing and a lower radial bearing which are provided to an upper part of the first rolling piston and a lower part of the second rolling piston respectively to support the rotation shaft in a radial direction thereof; and an axial supporting part which comprises a first supporting member which is provided between the driving motor and the upper radial bearing, and a second supporting member which is provided between the second rotation cam and the lower radial bearing.
 19. The air conditioner according to claim 18, wherein the axial supporting part supports an axial load of the rotation shaft when the rotation shaft rotates, and the upper radial bearing is distanced from the first rotation cam when the axial part is coupled to the rotation shaft.
 20. The air conditioner according to claim 15, further comprising a middle plate which is interposed between the first rotation cam and the second rotation cam, wherein at least one of the first rotation cam and the second rotation cam are distanced from the middle plate. 